A lingering cough can be contagious depending on the underlying cause of the cough. For example, if the cough is caused by a viral or bacterial infection, then it is likely contagious. Infections such as the common cold, flu, and COVID-19 can all cause a lingering cough and are highly contagious.
In addition, a lingering cough can also be caused by environmental factors such as allergies, asthma, and exposure to irritants like smoke and pollution. In these cases, the cough is not contagious, but it is still important to seek medical attention to determine the underlying cause and appropriate treatment.
It is always a good idea to practice good respiratory hygiene such as covering your mouth and nose when coughing or sneezing, washing your hands frequently, and avoiding close contact with others if you have a lingering cough or other symptoms of illness.